Cast-in-place structural truss slab and manufactured pan

ABSTRACT

A structural two-way truss slab of egg-crate form is provided with manufactured pans that have openings in the sidewalls thereof with interconnecting members between the openings. The arrangement is such that the pan can remain in place and thus provide a finished ceiling effect. The system further provides an ability to run air-conditioning, electrical, plumbing and other conduits through the slab itself after the slab has been poured. The slab is structurally equivalent to conventional two-way slabs but is of less gross weight.

United States Patent MacLean, III et a].

[ Feb. 8, 1972 [54] CAST-IN-PLACE STRUCTURAL TRUSS SLAB AND MANUFACTUREDPAN [72] Inventors: Charles C. MacLean, III; Alfonso Villa,

both of San Juan, PR.

[73] Assignee: l-lovey T. Freeman, Jr., Barrio Rio Guaynabo, PR.

[22] Filed: Sept. 19, 1969 2: Appl. No.: 859,289

[52] 11.8. CI ..52/337, 52/576, 52/577, 52/602, 249/28 [51] Int. Cl...E04b 1/16, E04b 5/16, E04b 5/26 [58] field of Search ..52/337, 602,576, 577, 323;

[56] References Cited UNITED STATES PATENTS 1,633,715 6/1927 Seelye..249/30 2,043,697 6/1936 Deichmann... ...52/602 2,534,580 12/1950Edwards ...52/602 2,592,634 4/1952 Wilson ..52/576 2,775,019 12/1956Bemis ..249/l76 2,892,238 6/1959 Budd 3,328,932 7/1967 Cheskin ..52/5763 ,495 ,367 2/1970 Kobayashi ..52/ 5 76 FOREIGN PATENTS OR APPLICATIONS166,683 1/1956 Australia ..52/337 551,370 1/1923 France ..52/477 PrimaryExaminer-F rank L. Abbott Assistant Examiner.lames L. Ridgill, .lr.AttorneyBarlow & Barlow [57] ABSTRACT A structural two-way truss slab ofegg-crate form is provided with manufactured pans that have openings inthe sidewalls thereof with interconnecting members between the openings.The arrangement is such that the pan can remain in place and thusprovide a finished ceiling effect. The system further provides anability to run air-conditioning, electrical, plumbing and other conduitsthrough the slab itself after the slab has been poured. The slab isstructurally equivalent to conventional two-way slabs but is of lessgross weight.

5 Claims, 9 Drawing Figures WENTED FEB 81972 3,640,040

sum 1 or 2 INVENTORS CHARLES C. MACLEAN III ALFONSO VILLA BY flawed WM,

ATTORNEYS PATENTED FEB 8l972 SHEET 2 OF 2 FIG.9

FIG?

I INVENTORS CHARLES c. MACLEAN 111 ALFONSO VILLA BY fluzup M ATTORNEYSCAST-IN-PLACE STRUCTURAL TRUSS SLAB AND MANUFACTURED PAN BACKGROUND OFTHE INVENTION At the present time the'building industry is utilizingreinforced concrete slabs for floor construction in multistorybuildings. To form the slabs, pan-type forms that are usuallymanufactured from steel or fiberglass and are generally square in planhave come into common use. A suitably supported plywood decking receivesthese pan-type forms in inverted relationship, and reinforcing rods,electrical conduit and plumbing provisions are made in the structurebetween adjacent pans before concrete is poured. After the slab ispoured, the steel pans are removed revealing an egg-cratetype ofconstruction underneath the slab which effectively is made up of anumber of intersecting T-beams. Air-conditioning ducts are then hungbeneath this egg-crate construction, and a ceiling is hung below theair-conditioning ducts in order to provide a finish appearance. Thismethod of' construction increases the overall height of the buildingssince the floor-tofloor dimension must take into account the hungceiling, and if changes are desired after the building is finished, suchchanges are limited by the original design insofar as plumbing andelectrical services are concerned which are located for the most partwithin the cast slab. One approach to providing voids throughout a castfloor structure is shown in the Leemhuis Pat. No. 2,602,323, but thissystem lacks flexibility since the voids once created cannot be utilizedafter the structure is poured since access thereto is blocked. Anotherapproach at utilizing voids was recently announced by the PortlandCement Association and is known as the Triposite building system. Inthis system precast concrete inverted double-T beams are supported bycast-in-place transverse beams in which voids are created in the floorfor utility and ventilation distribution, but here again the systemlacks complete flexibilityas a flooring structure is placed on top ofthe beams and SUMMARY OF THE INVENTION A structural two-way truss slabbuilt around an integral manufactured pan is provided with a grid workof voids throughout the slab that permit, within the thickness dimensionthereof, provision for continuous access to all mechanical andventilating installations that are run through the void system and toprovide in some cases, by suitable blocking of passageways, anintegrated ventilation system in which the voids are used aspassageways. The manufactured ceiling pan which is the heart of thesystem is preferably made from structural foam plastic which hasproperties of greater wall thickness per unit of weight so as to have alarge stiffness to weight ratio. With this type of material being usedas the celling pan, the surface appearance will remain consistent afterthe shores are removed, and flanges on the pans provide interlockinggrooves in which wall systems may be locked. The provision of the voidswithin the beam system, which reduces the gross weight of the slab, doesnot reduce the strength of the beam as a particular reinforcing rodstructure is used within the beams. The plastic also provides a goodanchor for screws, nails, staples and other fastening devices in commonuse, and in this way the voids in the egg-crate type of construction maybe utilized readily for hanging fluorescent fixtures and providingventilation and grillwork inserts and mechanical covers to hide themechanical work once the same is in place. The structural two-way trussslab system thus has the ability for ready access to any network ofducts, and as the building requirements change, it is much easier tomake requisite changes in plumbing, electrical and other mechanicalservices as well as reducing the cost of the overall building by afactor of at least 15 percent.

DESCRIPTION or THE DRAWINGS FIG. I is a perspective view partly insection of a poured slab with the pan construction of the inventionbefore removal of the slab supporting system;

FIG. 2 is a perspective view partly in section from the underside of thecompleted slab and with a portion showing the cover structure of FIG. 8in place;

FIG. 3 is a partial sectional view taken through one of the beamsillustrating the reinforcing rods and their possible placement toprovide proper strength;

FIG. 4 is a perspective view of a ceiling pan used in the system with aportion broken away;

FIG. 5 is a sectional view taken on lines S5 of FIG. 3 showing thegroove that is provided for interlocking with a vertical wall section;

FIG. 6 is a perspective view of an interconnecting hollow memberprovided between the pans;

FIG. 7 is a bottom plan view of one section underneath the pan with amechanical equipment cover structure in place;

FIG 8 is a perspective view of a cover structure; and

FIG. 9 is a perspective view of a light diffuser that may be used withinthe pan.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 4, it will beseen there is illustrated a form of pan construction for use in thebuilding system that may be utilized as a form in the pouring ofconcrete floors to produce a two-way truss structure. The pan generallydesignated 10 includes a top wall 12, sidewalls 11 with lower flanges14. The bottom face of the flanges designated 15 is provided with astepped construction to provide a groove 16 opening to the edge of theflange 14. Each sidewall 11 is provided with an aperture or opening 18of general triangular form with is apex downwardly providing a V, andsince the structure is contemplated to be molded from structural foamplastic, a number of reinforcing ribs are provided to retain properrigidity as, for example, ribs 19 on the sidewalls and a network of ribssuch as 20 on the top wall 12. To provide a good beam cross-sectionalarea, the sidewalls 11 are inclined slightly inwardly towards the topwall 12.

Referring now to FIG. 1, it will be seen that there is illustrated aslab construction in intermediate stage of forming. In followingpreferred building practice, there is first place supporting jacks 25arranged and held in a grid under the comers of each pan by stringers orother means, as for example a framework of removable beams 26, 27 whichare placed to be under the intersecting edges of the pans 10. Fans 10are then positioned on the supporting grid so that the flanges l4 abut.After the pans have been properly placed, reinforcing rods arepositioned between the pans. One form in which the reinforc ing rods maybe placed to properly form the truss slab construction is illustrated inFIG. 3. Here the reinforcing structure is made up of a number ofhorizontally oriented rods such as 30 in the bottom area of the slab andalso rods 31 in the top area of the slab which extend longitudinally ofthe beam. Additionally, a number of diagonal rods such as 32 areprovided to span the opening or aperture area 18 of the form, and aswill be seen, these are made up of a straight section 33 which is bentas at 34 into a diagonal section that extends as at 35 at an angle tothe general axis of the beam and thence a top or upper longitudinalsection 36. This arrangement may extend in right-angular directionsalong the right-angular extents of the beams. After the reinforcing rodstructure has been properly clipped in place, interconnecting members 40such as illustrated in perspective in FIG. 6 are placed between the panswhich members are tapered to the inclination of the sidewalls l l. Thesections 40 conform in shape and size to the openings 18 so that theywill tightly fit therein and are generally made up of molded sectionshaving flat inner and outer faces with a hollow center.

With this amount of preparation having been accomplished, concrete isthen poured onto the structure to form beams designated 45 in betweenthe pans and a floor slab 46 which overlies'the pans. After the concretehas set the supporting structure 25, the transverse members 26 and thebeams 27 are removed, and the entire slab construction isself-supporting. It will be noted that the pans 10 have left in thefloor construction to provide a finished ceiling appearance; as castthere will now be provided on at least a quarter relationship a numberof openings or apertures which have been designated 50 in the finishedstructure. Effectively, the openings 50 with the void provided by theunderside of the pan 10 forms a grid pattern of channels throughout thefloor into which mechanical, electrical and air-conditioning maybedirected. Each pan can be considered an individual cell which is themain constituent of a grid section in the floor. Since the piping'andother fixtures may provide an unsightly appearance in the openings ofthe pan, it is contemplated to cover the mechanical material with acover structure which has been generally designated 60 (FIG, 8).Referring to FIGS. 7 and 8, a typical cover construction for themechanical services has been illustrated, and this is made up of twointersecting truncated triangular structures 61 and 62 that are slightlylarger in cross-sectional form than the openings 18 provided by the pan10 with comers 63. Inasmuch as the pan 10 is preferably formed fromstructural foam plastic, it will readily accept fastening devices, andthis part 60 may be easily fastened in place particularly thru corners63 and easily removed. Altemately, it may be desired to utilize the openarea of the pan to fasten fluorescent lighting fixtures or the like, andin this case the fluorescent fixtures may be fastened in place and alight diffuser such as 64 illustrated in FIG. 9 may be fastened in placesubstantially at the lower edge of the pan 10. Further if thepassageways are utilized for air-conditioning, the cover 60 may bemodified to form a straight-thru, curved or T-connection duct section,and suitable air diffusers may likewise be fastened in place at outletpoints.

It will be recalled that grooves 16 are formed in the bottom edge of theflanges 14 of each of the pans. When the pans are in abuttingrelationship, this groove 16 (see FIG. has been formed in a convenientmanner so that vertical wall structures such as 65 may be receivedtherein. If, for example, the pans 10 are made with a maximum dimensionfrom one edge of one flange 14 to the opposite flange 14 of 5 feet, itwill be apparent that the grooves 16 will appear on 5-foot centers. Thiswill give extreme flexibility in the positioning of partitions foroffice building utilization, and practically any arrangement desired bya tenant can be had with a minimum of cost. It will be appreciated,however, that the dimensions may vary widely depending upon the spansinvolved, but a typical depth for the beam 45 may well be on the orderof 2 feet with a 2- to 3-inch slab over at the top wall of the pan 10.Typically the reinforcing bars 32 may be number 8 mild steel and thelongitudinal bars such as 30 and 31 may vary between what may typicallybe No. 7 mild steel, the particular type being dictated by the span andfloor loadings to be expected.

While not specifically illustrated, it will be apparent that to provideproper duct work for air-conditioning systems as mentioned above, itwill become necessary to block off some of the openings formed by thegrid work as cast, but this can be readily achieved if integral ductingis desired by the use of plates that may be screwed over the openings 18of an individual pan, and further, of course, turns may be accomplishedby the use of deflectors similarly fastened to the pan in a modifiedform of a cover such as 60 which lends itself admirably to thisparticular usage as the same is preferably molded out of structural foamplastic.

We claim:

1. A structural twoway beam truss slab comprising a slab of concretehaving integrally formed therebeneath a plurality of supportingintersecting beams arranged in a grid, said grid made up of a pluralityof grid sections each having individual cells formed by inverted plasticpans open at their bottom and whose top walls are firmly attached to theunderside of the slab and whose sidewalls are firrnl downwardlyextending walls formed y said beams, the

sidewalls of selected adjacent pans having aligned openings ofsubstantial cross section, horizontally elongated interconnectingmembers of substantial cross section that conform in size and shape tothe openings in the sidewalls of said pans, the op posite ends of saidinterconnecting members inserted in tightly fitting engagement in saidopenings in the sidewalls of said pans, and reinforcing members in saidbeams that produce a beam grid system of concrete formed with a networkof apertures therethrough.

2. A structural two-way beam truss slab as recited in claim 1 whereinsaid pans have horizontally outwardly extending flanges at their bottomswith said adjacent pans having their flanges in abutting relationship,said flanges having an upwardly recessed sector at their outer peripheryto form between the abutting flanges of said adjacent pans a channelwhich may receive a vertical wall structure.

3. A structural two-way beam truss slab as recited in claim 1 whereinsaid openings are V-shaped and the reinforcing members in the beamsinclude a number of longitudinal reinforcing rods and a number ofangularly bent rods whose angular portion thereon is substantiallyparallel to the inclination of the V-shaped opening in each beam.

4. A structural two-way beam truss slab as recited in claim 1 whereinsaid horizontally elongated connecting members are hollow.

5. A structural twoway beam truss slab as recited in claim 1 furthercomprising covers for said cells essentially formed by two intersectinghollow truncated triangular structures that are slightly larger incross-sectional form than said openings in said pans with web comersconnecting their top edges.

attached to the

1. A structural two-way beam truss slab comprising a slab of concretehaving integrally formed therebeneath a plurality of supportingintersecting beams arranged in a grid, said grid made up of a pluralityof grid sections each having individual cells formed by inverted plasticpans open at their bottom and whose top walls are firmly attached to theunderside of the slab and whose sidewalls are firmly attached to thedownwardly extending walls formed by said beams, the sidewalls ofselected adjacent pans having aligned openings of substantial crosssection, horizontally elongated interconnecting members of substantialcross section that conform in size and shape to the openings in thesidewalls of said pans, the opposite ends of said interconnectingmembers inserted in tightly fitting engagement in said openings in thesidewalls of said pans, and reinforcing members in said beams thatproduce a beam grid system of concrete formed with a network ofapertures therethrough.
 2. A structural two-way beam truss slab asrecited in claim 1 wherein said pans have horizontally outwardlyextending flanges at their bottoms with said adjacent pans having theirflanges in abutting relationship, said flanges having an upwardlyrecessed sector at their outer periphery to form between the abuttingflanges of said adjacent pans a channel which may receive a verticalwall structure.
 3. A structural two-way beam truss slab as recited inclaim 1 wherein said openings are V-shaped and the reinforcing membersin the beams include a number of longitudinal reinforcing rods and anumber of angularly bent rods whose angular portion thereon issubstantially parallel to the inclination of the V-shaped opening ineach beam.
 4. A structural two-way beam truss slab as recited in claim 1wherein said horizontally elongated connecting members are hollow.
 5. Astructural two-way beam truss slab as recited in claim 1 furthercomprising covers for said cells essentially formed by two intersectinghollow truncated triangular structures that are slightly larger incross-sectional form than said openings in said pans with web cornersconnecting their top edges.